Method of sealing metal in glass.



PATENTBD APR. 9; 1907.

G. H. MBEKBR. METHOD OF SEALING METAL IN GLASS.

APPLICATION FILED JUNE 19, 1906.

ITTURNEYL llhll i lilfi STTES a'rnn'r errron GEORGE H. MEEKER, OF MEDIA, PENNSYLVANIA.

Specification of Letters E'atent.

ratented April 9, 190?.

Application filed June 19,1906. I Serial No. 3Z2.l02.

To all whom may concern.-

Be it known that I, Gnonen H. Mnnxnn, a citizen of the United States, and a resident of Media, Delaware county, State of Pennsylvania, have invented certain new and useful Improvements in Methods ol Sealing Metal in Glass, of which the following is a full, clear, and exact description.

The object of this invention is to provides novel method of sealing oxidizable metal in glass to secure an absolutely tight joint between said glass and metal.

Although the invention may be useful for many purposes, it is particularly ada ted for use in connection with sealing into tie stem of anincandescent electric lamp the leading in wires to which the usual carbon filament is attached within the lamp, and I shall there fore describe my invention as applied to such In the well-known incandescent electric lamp it is necessary to use platinum wires extending from. the termini of the carbon filament within the lamp into the inner end of the stem of the lamp, the inner end of which stem is sealed upon said platinum wires, thereby securing an air-tight joint. Many attempts have been made to reduce-the amount of platinum wire necessary for this purpose, as it is quite expensive; but it has been found impossible heretofore to do away entirely with the use of platinum wires because in the process of sealing the wire in the stem it is absolutely essential that an air-tight joint between the Wire and the glass shall be roduced, and platinum is the only metal aving substantially the samecoeflicient of heat expansion and contraction as the lass which will not oxidize when subjectc with the glass to the heat necessary to render the glass plastic that it may be scaled down upon the wires. V

In carrying out my invention I use a nickel-steel or nickel-iron which can be pro duced having substantially the same coeihcient of heat expansion and contraction as; glass. This metal, however, rapidly oxidizes when subjected to heat in the presence of an.

The usual method oi sealing wires into the glass is to extend the usual copper wires hav-.

ing the short platinum wires joined to theupper ends thereof into the lower end of the tubular stem, so that the free ends of the latinum wires will project a short distance eyond the inner end of the stem, and the other ends thereof will be within the stem. The wires and inner end of the stem, being retained in this position, are heated in a burner until the said end of the glass stem becomes plastic, whereupon the operator by a suitable'tool squeezes the walls of the inner end of the stem together, thereby securely sealing the wires within the said stem. This heating of the platinum wires at the sametiine the glass is heated does not affect said wires in any way to revcnt the formation of an air-tight joint etween said wires-and the glass stem. If nickel-steel or nickel-iron wires having substantially the same coefiicient of heat expansion as the glass be substitutcd for the platinum wires and subjected to this method of treatment, the nickel-steel or nickel-iron when heated in the presence of air with the glass will be come oxidized and after the glass is squeezed down to form the seal between the stem and said wires an air-tight j dint will frequently not be secured because the air will sometimes leak through this oxid coating on the wires into the lamp.

In carrying out my present invention I place the nickel-steel or nickel-iron wires in drawn from said heat and brought to a posi-' tion inclosing said wires, whose ends project the required distance through the inner end of said stem, and the plastic inner end of the stem is by suitable manipulation quickly squeezed down upon said wires, thereby sealing the same into the glass before said wires have had opportunity to become heated to oxidizing temperature, whereby an absolutely air-tight joint is secured between the wires and the glass. Y

In the accompanying drawings I have illustrated diagrammatically my method as aplied to the stem of an incandescent electric amp.

Figure 1 shows the wires win a position exterior to the stem 8, the inner end of which is being heated to plastic condition by a circular burner 7n Fig. 2 shows the stem removed from the burner-flame and encompassing the wires, the inner end of the stem having been squeezed together to seal the wires within the same. V

' I have not deemed it necessary herein to describe the operation of assembling the stem within the lanip-hulh and securing the same thereto nor of how we outer ends of the wires to are secured to the usual lamp-cap i do notwish to he understood as limiting niyseh to the use of nickel-steel or nickel-iron alone in carrying out my process, for other I i metals which would oxidizewhen heated in l the presence of air may be substituted for the 1 fore said wires have become heated to ()XdllZ I nichetsteel or nickel-iron. Nor is it essential that either the glass or the metal be moved with relation to each other in my process, as the metal 1na be held in proper relation to the glass during the heatingol the 3 letter or be inclosed in a removable h nt-insulator, such an asbestos covering, which when the glass has been heated to plastic 5 condition would he removed and the glass I quickly sealed upon the metal before it had glass to plastic condition without heating the iidizuig teumorature, and soqulckly 3 wirolo pressing the plastic glass arouiul said-wire that the wire Wlll be sealed therein and the l air excluded therefrom before said wire hrs l become heated to oxidizing teuuperature, substantially asset forth. i

2. The process of sealing oxidizablc wires Within incandescent lamp stems which ronto plastic condition without heating said wires to oxidizing temperature, and so quickly p 'essinp; the plastic portion of said stem together that the wires will be sealed therein and the air excluded therelrom being temperature, substantially as set forth.

3 The process of sealing oxidizable wires within inramleseent-lmnp stems, said Wires having substantially thesame eoellicieut of 1 heat expansion and contraction as the stein, whichcousists in heating a portion of the tubular stem to plastic condition,. at a point away from said Wires, bringing the tubular stem to position,inelosint said wires, and pressing the plastic portion of the stem together,-embodding said wires therein before 5 they have become heated to oxidizing temperature.

: fixed my signature.

GEORGE l sists in heating; a portion of the tubular stem.

in testimony whereof I have hereunto al 

